Service manual
Table Of Contents
- Installation, Operation & Service Manual
- UHA-Series
- Tubular Unit and Utility Heaters
- (Low Profile Range)
- Manuel d’installation, d’operation, et de service
- UHA-Series
- Aérothermes Utilitaires à échangeur tubulaire
- (Gamme compacte)
- TABLE OF CONTENTS
- SECTION 1: Heater Safety
- SECTION 2: Installer Responsibility
- SECTION 3: Critical Considerations
- SECTION 4: Clearances to Combustibles
- SECTION 5: National Standards and Applicable Codes
- SECTION 6: Heater installation
- SECTION 7: Venting
- 7.2.1 United States Requirements
- 7.2.2 Canadian Requirements
- 7.3.1 Standard Vented Heaters (Models UHA[X] 30 - 125)
- 7.3.2 Separated Combustion Heaters (Models UHA[X]S 30 - 125)
- 7.7.1 Maximum Vent Lengths Table
- 1. Seal any unused openings in the venting system.
- 2. Inspect the venting system for proper size and horizontal pitch, as required by the NFPA 54/ ANSI Z223.1 - latest revision, National Fuel Gas Code (US) or Standard CSA B149.1 Natural Gas and Propane Installation Code (Canada) and these instruction...
- 3. Close all building doors and windows and all doors between the space in which the appliance(s) connected to the venting system are located and other spaces of the building. Turn on clothes dryers and any exhaust fans, such as range hoods and bathr...
- 4. Follow the lighting instructions. Place the appliance being inspected in operation. Adjust thermostat so that the appliance will operate continuously.
- 5. For any appliance having a draft hood, test for draft hood appliance spillage at the draft hood relief opening after five minutes of main burner operation. Use the flame of a match or candle.
- 6. After it has been determined that each appliance connected to the venting system properly vents when tested as outlined above, return doors, windows, exhaust fans, fireplace dampers and any other gas-burning appliances to their previous conditions...
- 7. If improper venting is observed during any of the above tests, the venting system must be corrected by a contractor qualified in the installation and service of gas-fired equipment or your local gas supplier. If the venting must be resized, use ap...
- Figure 9: Vent and Roof Detail
- Figure 10: Standard Vented Heater - Vertical and Horizontal Vent Termination
- Figure 11: Standard Vented Heater - Common Vertical Vent Termination
- Figure 12: Separated Combustion Heater - Vertical and Horizontal Vent Termination
- Figure 13: Concentric Vent Box
- Figure 14: Concentric Vertical and Horizontal Vent Termination - Separated Combustion Heater
- SECTION 8: Air Supply
- SECTION 9: Gas Piping
- SECTION 10: Wiring
- SECTION 11: Operation and Maintenance
- 11.1.1 Louvers
- 11.1.2 Electrical Checks
- 11.1.3 Gas Supply
- 11.1.4 Mechanical Checks
- 11.2.1 Before Operating the Heater
- Figure 16: Automatic Burner Control Sequence
- Figure 17: Gas Valve for Models UHA[X][S] 30 - 45
- Figure 18: Gas Valve for Models UHA[X][S] 60 - 125
- 11.2.2 Start-Up the Gas Valve (All Gases)
- 11.2.2.1 Check Burner Gas Pressure
- 1. Remove the plug in the outlet (burner) pressure test point and connect a pressure tap and a manometer.
- 2. With the burner firing, measure the pressure on the manometer. To adjust the burner pressure, remove the regulator cover from the valve and turn the regulator adjustment screw to set the required burner pressure as stated in the Technical Data Tab...
- 11.2.2.2 Check Gas Rate
- 1. After burner pressure adjustment, allow the heater to operate for at least 15 minutes and then re-check settings. Adjust pressure setting if necessary.
- 2. Check gas flow rate at gas meter.
- 3. Turn off heater and electrical supply.
- 4. Remove the manometer and refit all covers to the valve and tighten the screw of the outlet pressure tap.
- 11.2.2.1 Check Burner Gas Pressure
- 11.2.2 Start-Up the Gas Valve (All Gases)
- SECTION 12: User Instructions
- SECTION 13: Servicing
- 1. Open the hinged door and remove from the hinges. Set door aside. See Page 46, Section 15.2.
- 2. Remove burner side panel. Electrode and flame probe should remain attached. See Page 47, Section 15.3.
- 3. Remove burner assembly from cabinet via four screws, two on top and two on bottom. Clean any deposits from the main burner which may have formed in the injectors or venturi of the burner.
- 4. Check condition of ignition electrode and flame probe. Clean off any deposits which may have formed, check condition of ceramic insulators. Replace as required. See Page 47, Section 15.3.
- SECTION 14: Troubleshooting
- SECTION 15: Replacement Parts
- See warnings and important information on Page 37, Section 13 before removing or replacing parts.
- Burner Components All serviceable burner parts are accessed by the hinged door on the side of the heater.
- 15.1 Gas Valve
- 15.2 Burner Injectors
- 15.3 Ignition Electrode and Flame Probe
- 15.4 Heat Exchanger
- 15.5 Louver and Louver Springs
- 15.6 Flue Blower Vertical Installation
- 15.7 Pressure Switch
- Pull off 3 way connector. Spring open plastic clips of mounting cradle. Replace with correct type of pressure switch for model. The pressure switches are color coded for each pressure setting. Carry out a start-up after working on or changing a press...
- The control mounts to the heat exchanger plate. Pull out ignition cable and wiring from board, noting their positions. Release the four mounting standoffs. Refit in reverse. Ensure correct location of ignition cable and all other wiring.
- The axial fan unit for the heater is supplied completely assembled and balanced.
- SECTION 16: Specifications
- SECTION 17: ADDISON® UHA-Series Warranty

UHA LOW PROFILE UNIT HEATER INSTALLATION OPERATION AND SERVICE MANUAL
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Figure 19:
Reset Button
To reset manual reset limit switch, press reset
button. NOTE: To reset, the switch must be cool.
Description Part Number
Manual Reset Limit Switch 90412106
Manual Reset Limit Switch
12.3 Lighting Instructions
12.3.1 To Turn On Heater
1. Ensure that the electrical and gas supplies to
the heat
er are on. Check that the on site
controls are "ON".
IMPORTANT:
The thermostat setting must be above
the ambient temperature for the heater to operate.
2. The automatic firing sequence will begin as
descr
ibed on Page 32, Figure 16. The heater
will now operate automatically under the control
of the on sit
e controls.
12.3.2 To Turn Heater Off
Set the thermostat to the "OFF" position.
The burner will turn off immediately.
The fan will continue to run for 90 seconds.
To restart, turn the thermostat above room
t
emperature.
12.4 Simple Troubleshooting
Some possible reasons for the heater not operating
ar
e:
1. Gas supply not "ON".
2. Electricity supply not "ON".
3. The time and/or temperature controls are not
"ON".
4. A limit switch may have operated. This may be
caused b
y an interruption of the electrical
supply, failure of the distribution fan or vent or
heat exchanger blockage.
If a temperature limit switch persistently trips, there
is a f
ault which must be investigated by a contractor
qualified in the installation and service of gas-fired
heating equipment.
12.4.1 Simple Troubleshooting (Burner Faults)
If the burner fails to ignite for any reason, it will retry
f
or ignition (four trials total). After four unsuccessful
ignition trials, the control will put the heater into
lockout for one hour.
Lockout should not occur during normal operation of
the heat
er and indicates there is a fault condition
which must be corrected. There is an LED light on
the ignition control that flashes codes to assist in
fault correction. See Page 36, Figure 20 for LED
indication codes.
Figure 20:
LED INDICATION FAULT MODE
Slow Flash Normal Operation - No call for heat.
Fast Flash Normal Operation - Call for heat.
2 Flashes Ignition Lockout - No flame detected.
3 Flashes Airflow Fault - Pressure switch open or closed.
4 Flashes Temperature Limit or
Manual Reset Limit Switch Open
5 Flashes Flame Sense Error - Gas valve not energized.
Steady On Internal Control Failure
LED Diagnostic Codes










